Anita Mk VII
Photograph courtesy of Frank Eggebrecht, via Friedrich Diestelkamp.
Anita Mk VII
The Anita Mk VII, made by the Bell Punch Co. of Uxbridge, England, was launched in October 1961[1]. It was sold mainly in continental Europe, and was announced in Germany by the distributor Büromaschinen-Vertriebsgesellschaft m.b.H. Together with the concurrently introduced Anita Mk 8, for the British market, it was the world's first electronic desktop calculator.
Development of the Anita calculators was started in 1956 under Norbert Kitz (a.k.a. Norman Kitz), who had worked on the pilot version of the ACE (Automatic Computing Engine) computer project in the mid 1940s.
The name ANITA, stands variously for "A New Inspiration To Arithmetic" and "A New Inspiration To Accounting". This became the family name for all the Bell Punch electronic models, which were distributed by Sumlock Anita Ltd.
The photographs show the machine with model/serial number C/VII/0510/A.
The Anita is a full-keyboard calculator with a 13-digit "Nixie" type tube display, and makes extensive use of cold-cathode vacuum tubes, and an "integrated circuit" of the vacuum tube era - the Dekatron decimal counter tube (see photographs below).
The Mk VII model was sold mainly in continental Europe, especially Germany, Holland, and Belgium.
The column of keys on the far left are the "tabulator keys". Pressing one of these moves the number being displayed so that its decimal point is in the selected position. For example, assume that as a result of previous calculations the display shows 1.53 on the far right of the display, with the decimal point in position 2 between the 2nd and 3rd number indicator tubes. Now, if the next step in the calculation is to add 0.2368 then we cannot do this since the 6 and the 8 are off the keyboard and display to the right. In this case, with the 1.53 being displayed, the tabulator key marked "4" is pressed and the whole number moves on the display to put the decimal point in position 4 so that the display will show 1.5300. The second number, 0.2368, and now be added with no loss of accuracy.
Initially this model used several Dekatron counter tubes. One produced a series of pulses for continuously scanning the number keys on the keyboard. Another was used to position the decimal point in the display and alter its position during multiplication and division. This Dekatron stayed in a fixed state, illuminating one of the decimal point indicators for extended periods which caused problems with sputtering of metal from the energised electrode. The circuit was soon modified to eliminate this Dekatron and cure this problem.
'Büromaschinen-Mechaniker' announced that the Mk VII would be Anita Mk 8, as sold elsewhere.
